The invention relates to rolling gear apparatus for use in a gear cutting machine forming involute teeth from toothed wheel gear blanks.
Apparatus of the above kind (DE-PS 2,009,593) are already known that are adjustable for different base circle diameters of the involute. To produce the necessary rolling movement of the gear blank, two carriages are provided. A primary carriage moves back and forth on top of a column while a secondary carriage moves back and forth in a direction transverse to the first carriage and is adjustable on its base. The two carriages alternatively are driven by means of a spindle. The primary carriage provides the translation portion of the rolling movement to the apparatus system. The second secondary carriage operates with a sliding block which glides in a guideway set on an angle around a center of rotation to produce the rotational portion of the rolling movement. The sliding block is connected with the secondary carriage and can be adjusted back and forth in the guideway. The working part that is to be operated on, that is machined, will be turned around an arched path that is determined in each case by the angle of the guideway, the working part being turned by a roll-circle. The roll-circle is connected with the secondary carriage, while the guideway that is set at an angle is arranged on an engine bed.
With this known type of apparatus, the guideway of the secondary carriage is precisely at a right angle to the movement path of the primary carriage. The angle position of the guideway is set at a mathematically predetermined value to select the different base circle diameters. Thus, the roll motion of the working-part to be operated on, which is necessary for an involute-tooth forming system, is assured. The disadvantage with this type of apparatus is the relatively low selectivity of setting the desired base circle diameter in any case. Thus, for example, to change the base circle diameter of the roll-circle arch, many values from zero (0) degrees to ninety (90) degrees are required.
The task of the invention presented is to develop the rolling gear apparatus of the kind mentioned so that an increased selectivity is made possible when setting the appropriate base circle diameter. This task is accomplished in accordance with the invention in that the movement path of the secondary carriage runs at an oblique angle or angle to the movement path of the primary carriage. Thereby, in both a simple manner and as a result of the slanted position of the movement path of the secondary carriage, a significantly improved selectivity of setting the selected base circle is accomplished.
Optimal conditions are then present in a further embodiment of the invention when the movement path of the secondary carriage runs at a 45.degree. angle to the movement path of the primary carriage; thus, the selectivity is increased by a factor of the square root of 2(.sqroot.2).
According to a further embodiment of the invention, the secondary carriage can be connected with the drive means of the rolling gear apparatus, the working-part table can be connected with the drive means of the rolling gear apparatus, or the primary carriage can be connected with the drive means of the rolling gear apparatus.
Further, it is possible that with two drives either the primary and secondary carriages can be driven or the primary carriage and the working-part table can be driven.
According to another feature of the invention, the primary and secondary carriages are each provided with a longitudinal movement indicator. Alternatively, the primary carriage is provided with longitudinal movement indicator and the working-part table is provided with an angular movement indicator. Thus, in an advantageous way, as a result of the effect of the individual indicators and the angularly adjustable guideway of a crank element, an exact setting of the base diameter is obtained.
According to another feature of the invention, the secondary carriage is provided with an element for obtaining a cutting advance. This element can be adjusted and can be set between two stops whereby the entire unit is adjustable and can be set to carry out the separation between two stops. Further, the working-part table and roll-circle are equiped with a coupling. Both stops can be built to be adjustable whereby, according to another feature of the invention, the coupling in each case consists of a diaphram ring impacted upon by a medium, the diaphram ring being in operative connection with a lamella. Thus, a simple way, the possibility exits for providing a cutting advance, compensation for play as well as for carrying out separation stepping free from play.